Load-securing device

ABSTRACT

The invention provides a device for securing the upper terminal position of a liftable and lowerable object, comprising cable means having a hoist-side end and an object-side end; a stationary bracket having an aperture disposed in a substantially horizontal plane; a housing supported by the object-side end of the cable means and carrying the object, the housing having a lower portion and an upper portion, at least the upper portion being configured to pass through the aperture, a first opening at the top of the upper portion and a second opening at the bottom of the lower portion facilitating the passage of the cable means through the housing, and two oppositely located, elongated slots extending along at least parts of the upper portion; lever means located inside, and extending through a substantial portion of, the housing, the lever means being pivotably mounted in the lower portion of the housing and being provided with catch means and camming means, the lever means having a first limit position in which the camming means protrudes through one of the elongated slots, and a second limit position in which said catch means protrudes through the other one of the elongated slots, and spring means adapted to act on the lever means and biasing the lever means towards the second limit position.

This application is a divisional of application Ser. No. 09/614,263filed Jul. 12, 2000.

FIELD OF THE INVENTION

The present invention relates to a device for securing the upperterminal position of a lowerable and liftable object, in particular, aspare tire for a vehicle.

BACKGROUND OF THE INVENTION

Spare tires for vehicles are mostly heavy and bulky objects that, inmany vehicles, are accommodated below the vehicle body and are securedagainst the bottom of the vehicle or against a structure carried byelements of the vehicle chassis. Because of their weight and size,vehicle spare tires can rarely be lowered to the ground, nor raised forstorage, by hand. For this reason, heavier vehicles are provided withhoisting devices such as winches, by means of which the spare tire islowered or raised using a steel cable.

Steel cables, however, are liable to snap or break due to a number ofcauses, all of which are relevant to their use for the above-mentionedpurpose: lack of maintenance, corrosion due to exposure to theenvironment, fatigue due to vibration-enhanced stresses, and the like. Ahoisting cable failure could cause the spare tire to break loose fromits anchorage; should this happen in mid-travel, it would seriouslyendanger not only the vehicle itself, but even more so, other road usersbehind or alongside it.

A safety device to prevent such accidents is known from U.S. Pat. No.4,254,939, which provides a device consisting of two hollow uprights, ineach of which travels a cable-operated carriage supporting the load tobe raised or lowered. In case of cable failure, springs activate asystem of levers, causing a roller to be wedged into a tapering gapbetween the body of each carriage and an inside wall of the uprights.The braking force produced is thus purely frictional.

SUMMARY OF THE INVENTION

It is therefore one of the objects of the present invention to provide adevice that, in case of cable failure, will prevent the detachment of aload from its point of anchorage by positive action, rather thanreliance on friction.

It is a further object of the present invention to ensure that the loadis automatically secured once it is raised to its upper position of restand that it is automatically released from its secured state upon itsbeing controlledly lowered from that position.

According to the invention, the above object is achieved by providing adevice for securing the upper terminal position of a liftable andlowerable object, comprising cable means having a hoist-side end and anobject-side end; a stationary bracket having an aperture disposed in asubstantially horizontal plane; a housing supported by said object-sideend of said cable means and carrying said object, said housing having alower portion and an upper portion, at least the upper portion beingconfigured to pass through said aperture, a first opening at the top ofthe upper portion and a second opening at the bottom of the lowerportion facilitating the passage of said cable means through saidhousing, and two oppositely located, elongated slots extending along atleast parts of said upper portion; lever means located inside, andextending through a substantial portion of, said housing, said levermeans being pivotably mounted in the lower portion of said housing andbeing provided with catch means and camming means, said lever meanshaving a first limit position in which said camming means protrudesthrough one of said elongated slots, and a second limit position inwhich said catch means protrudes through the other one of said elongatedslots, and spring means adapted to act on said lever means and biasingsaid lever means towards said second limit position.

The invention further provides a device for securing the upper terminalposition of a liftable and lowerable object, comprising cable meanshaving a hoist-side end and an object-side end; a stationary brackethaving a rear wall and two lateral walls and provided with bearingmeans; lever means located between the two lateral walls of said bracketand provided in its upper portion with journals whereby said lever meansis pivotably mounted in the bearing means of said bracket and can assumefirst and second limit positions of tilt, said lever means beingprovided with gripper means at its lower end; plunger means carryingsaid object and kinematically connected to said cable means, saidplunger means having a central bore through which said cable meanspasses, and first spring means attached to said stationary bracket andbiasing said lever means towards the second limit position; wherein, inthe first limit position of said lever means, tension in the cable meanscauses the lever means to tilt towards the bracket rear wall, therebypermitting said plunger means to enter a space defined by said levermeans and said rear wall, thus forcing said lever means into the secondlimit position with the gripper means of the lever being locatedsubstantially vertically below the head of said plunger means, whereby,in case of cable failure, said first spring means forces the lever meansinto the second limit position and the plunger head is intercepted andretained by said gripper means.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in connection with certain preferredembodiments with reference to the following illustrative figures so thatit may be more fully understood.

With specific reference now to the figures in detail, it is stressedthat the particulars shown are by way of example and for purposes ofillustrative discussion of the preferred embodiments of the presentinvention only, and are presented in the cause of providing what isbelieved to be the most useful and readily understood description of theprinciples and conceptual aspects of the invention. In this regard, noattempt is made to show structural details of the invention in moredetail than is necessary for a fundamental understanding of theinvention, the description taken with the drawings making apparent tothose skilled in the art how the several forms of the invention may beembodied in practice.

In the drawings:

FIG. 1 is a cross-sectional view of a first embodiment of the deviceaccording to the present invention, in a first stage of its operation;

FIG. 2 is a perspective view of the bracket of the device according tothe invention;

FIG. 3 is a view in cross-section along plane III—III of FIG. 1;

FIG. 4 is a perspective view of the assembled housing of the device;

FIG. 5 is a side view of the housing of the device;

FIG. 6 depicts the device in a second stage of its operation;

FIG. 7 represents the situation following a cable failure;

FIG. 8 shows the device being pulled up without the load;

FIG. 9 is a cross-sectional view of a second embodiment of the deviceaccording to the invention, in a first stage of its operation;

FIG. 10 is a perspective view of the upper part of the housing of thedevice;

FIG. 11 is a top view of the upper housing part in cross-section atabout the middle of its height;

FIG. 12 is a perspective view of the lower housing part;

FIG. 13 shows the nested levers at a larger scale;

FIG. 14 is a perspective view of the camming lever;

FIG. 15 provides an inside view of the camming lever;

FIG. 16 is an elevational view of the catching lever;

FIG. 17 shows the catching lever as seen in the direction of arrow A inFIG. 16;

FIG. 18 represents the device according to the invention in thenon-loaded state;

FIG. 19 illustrates the continued hoisting process after the positiondepicted in FIG. 9;

FIG. 20 represents the situation after completion of the hoistingprocess;

FIG. 21 depicts the situation following a cable failure;

FIG. 22 is a cross-sectional view of another embodiment of the deviceaccording to the invention in a first operational stage;

FIG. 23 is a perspective view of the bracket of FIG. 22;

FIG. 24 is a perspective view of the lever of FIG. 22;

FIG. 25 represents a second stage of operation of the embodiment of FIG.22, and

FIG. 26 illustrates the situation in the device of FIG. 22 following acable failure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to the drawings, there is shown in FIG. 1 a first,preferred embodiment of the invention in a first stage of its operation,in which a load is being raised or lowered. Seen is a bracket 2, shownto better advantage in FIG. 2, which is fixedly attached to a member ofthe vehicle's chassis with the aid of lugs 4, advantageously welded to atubular body 6 of a substantially square cross-section. A cutout 8 (FIG.2) makes room for the above-mentioned chassis member. A plate 10 with adownardly flaring aperture 12 is fixedly attached to the end of body 6.The wall portion opposite cutout 8 is provided with a vertical slot 14,through which is introduced the bend end of a guide tube 16accommodating a steel cable 18 coming from a hoisting device (not shown)and ending in a ferrule 19. Guide tube 16 has a flaring end 20 whichrests against a crossbeam 22 of an inverted U-shaped cross-sectiontraversing body 6 via a pair of window-like openings 24 in the sidewalls of body 6. The height of openings 24 is much larger than thethickness of crossbeam 22, which, in this operational stage, anddepending on the weight of the load, is held up against, or at aposition close to, the upper limits of openings 24 by means of twohelical compression springs 26, the lower ends of which abut against andare held in position by two lugs 28 fixedly attached to the side wallsof body 6. The full purpose of springs 26 will be discussed furtherbelow.

Cable 18 is the load-carrying member of the device, with the load beingrepresented by the wheel disk WD of a spare tire. On its way down fromguide tube 16, cable 18 passes through the aperture 12, enters a splithousing 32 (of which only one half is shown) via a first opening, 34,and leaves it via a second opening 36.

Housing 32 is a split housing held together in assembly by bolts (notshown), and is seen in perspective in FIG. 4. Housing 32 has abottle-like shape, with an upper, neck-like portion 38 and a lower,bulbous portion 40 flattened on both sides (FIGS. 4, 5). Part of upperportion 38 is provided with recesses 42, which, in conjunction with thesecond half of split housing 16, form window-like slots 44, the purposeof which will become apparent further below.

A side view of the (empty) split housing 32 is shown in FIG. 5, fromwhich it is seen that the two halves of split housing 32 are not fullyidentical: recesses 42 are formed only in the left housing half, and thewindow-like slots 44, formed when the two housing halves are puttogether, are therefore not in the central plane of housing 32.

Inside housing 32 there is seen a lever 46 pivotable at its lower endabout a pivot 48 seated inside a hub 49 and extending through asubstantial portion of housing 32. Lever 46, advantageously made of flatsteel, is provided on one of its edges with a nose-like catch 50, and onthe other one of its edges, with a camming projection 52 having cammingsurfaces 54 and 56. Lever 46 can assume two limit positions of tilt: afirst position in which camming projection 52 protrudes from housing 32as is seen in FIG. 1, and a second position in which catch 50 protrudes.

Further seen is a projection 58 provided in the middle portion of lever46, the shape of which is seen to better advantage in FIG. 3. As shownin FIG. 1, cable 18, merely touching the surface of lever 46, contactsprojection 58 and, because of its tension, maintains lever 46 in theabove-mentioned first position in which camming projection 52 protrudesfrom housing 32 against the biasing force of a flat spring 60.

Wheel disk WD is supported by a wheel retainer 62, configured to beslipped through the wheel disk bore and become located below wheel diskWD. The entire load rests on ferrule 19.

The next operational stage is represented in FIG. 6. Here, the device isshown in its uppermost, secured position, with the tire fully raised andabutting against the supporting structure. On its way up from theposition illustrated in FIG. 1, the slanted camming surface 54 hasencountered the flaring surface of aperture 12, due to which lever 46has been forced into the second limit position, in which catch 50 nowprotrudes from housing 32. Any further movement upwards stabilizes thatposition when the vertical camming surface 56 contacts the rim ofaperture 12. At the same time, projection 58 is forcibly deflectingcable 18 from the straight line it followed in FIG. 1, putting it underadditional tension and making sure that the next time the spare tire islowered, cable 18, overcoming spring 60, will act to return lever 46 tothe first limit position as soon as camming surfaces 54,56 have passedbelow the rim of aperture 12.

It is also seen that springs 26 are almost fully compressed. This isachieved by operating the hoisting device beyond the point when theraised tire has made contact with the vehicle bottom or the structureagainst which it is to be secured. This produces additional tension incable 18, which, acting on the bent end portion of guide tube 16, flexesthe relatively long guide tube downwards, causing its flared end 20 toexert pressure on crossbeam 22, to compress springs 26. The energy thusstored in springs 26 is used to compensate for a possible reduction oftire width due to loss of air, ensuring that friction between the tireand the abutment structure will always remain sufficiently high toprevent a tire from working itself loose.

A situation of cable failure or break is depicted in FIG. 7. From theinstant camming surfaces 54, 56 have passed beyond aperture 12, lever 46is maintained in the second limit position by spring 60, which is nolonger opposed by the broken cable 18, and catch 50 is thus interceptedby the rim of aperture 12, which, of course, breaks the fall.

While in the event of cable rupture the spare tire remains safelysecured to the vehicle, removal of the tire for repair of the hoistingdevice can only be carried out in service stations equipped with meansto raise the tire high enough to detach wheel retainer 62 from wheeldisk WD. Housing 32 can then easily be removed from bracket tube 6 byinserting a tool such as a screw driver into a hole 64 in housing 32 andapply it laterally against a notch 66 in lever 46, thereby rotatinglever 64 in the clockwise sense, until catch 50 becomes disengaged fromthe rim of aperture 12, at which instant housing 32 can be removed frombracket tube 6.

FIG. 8 illustrates a situation in which housing 32 is pulled up withoutthe tire and shows how it is prevented from entering bracket tube 6 andgetting caught by the rim of aperture 12. Raising load-free housing 32,cable 18 is practically without tension, permitting flat spring 60 toforce lever 46 into the second position, in which catch 50 protrudesfrom housing 32. When housing 32 now approaches bracket tube 6, uppersurface 68 of catch 50 will be stopped by the lower surface of plate 10,preventing housing 32 from advancing any further.

FIG. 9 shows a second embodiment of the invention in a first stage ofits operation, in which a load is being raised or lowered. Seen is thetubular end 70 of a bracket (not shown), which is fixedly attached to amember of a vehicle's chassis and the end of which is provided with acircular opening 72 provided with a re-entrant rim 74.

Cable 76 is the load-carrying member of the device, with the load beingrepresented by the wheel disk WD. On its way down from the hoistingdevice (not shown), cable 76 passes through circular opening 72 andenters a two-part housing 78 via a bushing 80 and ends in a headedferrule 82, to which it is fixedly attached. Ferrule 82, having a head83, is slidingly seated in the lower part 84 of two-part housing 78. Thesuitably shaped shoulders 86 of upper housing part 88 carry wheelretainer 89, similar in design to that shown in FIG. 1.

Two-part housing 78 is seen to better effect in FIGS. 10, 11 (upper part88) and FIG. 12 (lower part 84). Upper housing part 88 is advantageouslymade of a press-formed sheet metal stamping, rigidified by bulges 104,that is folded onto itself, until tabs 98, 98′, which are parts of theforked ends 100, 100′, meet, thereby defining the central plane ofhousing part 88. The folding operation produces two oppositely located,elongated, window-like slots 102, of which only one is seen in FIG. 10.The function of these slots will be explained further below. Also seenare holes 108, designed to accommodate pivots 94 (FIG. 9). FIG. 11 is atop view of housing part 88 in cross section, at about the middle of itsheight.

FIG. 12 shows the lower part 84 of housing 78. Rims 110 fit the insidediameter of skirts 106 of FIG. 10 and posts 112 fit the gaps betweenfork-like ends 100, 100′. Recesses 114 in posts 112 are filled by therespective ends of a lever system to be discussed presently. A centralhole 116 accommodates ferrule 82 of FIG. 9. In the assembled housing 78,holes 118 are obviously aligned with holes 108 of upper housing part 88.

The central element of this embodiment of the device is a nestedtwin-lever system pivotably mounted in housing 78. The system comprisesa camming lever 90 having a camming surface 92 and a catching lever 94provided with a nose-like catch 96. Both levers have a substantiallyU-shaped profile, 10 with the profile of camming lever 90 being wideenough for catching lever 95 to be nestable therein, as seen in FIG. 13.

The twin-lever system further includes a helical compression spring 120,one end of which is seated on a tongue-like projection 122 raised fromcamming lever 90, and the other end of which is seated on a similarprojection 124 raised from catching lever 95. In the stage of operationshown in FIG. 9, in which the spare tire is either raised or lowered,camming lever 90 fully projects from housing 78 and catching lever 88 isfully pulled inside housing 78, with spring 120 compressed.

The mechanics of the interaction of the various components will bediscussed further below.

FIG. 14 is a perspective view of camming lever 90. The substantiallyU-shaped profile is clearly seen, except for two wing-like projections126 which are configured to fit recesses 114 in posts 112 of lowerhousing part 89 (FIG. 12). Holes 128 are obviously meant to fit pivots94 (FIG. 9). Further seen are pairs of second and third inclined cammingsurfaces 130, 131, the purposes of which will become apparent furtherbelow.

FIG. 15 provides an inside view of camming lever 90, showing tongue-likeprojection 122 on which is seated spring 120 (FIG. 9). Also clearly seenis heel 132 which, as will be shown, has an important function in themechanics of the device. Cut-out 134 provides a free passage to cable76. When cable 76 is under load, heel 132 is always in contact with head83 of ferrule 82.

FIG. 16 is an elevational view of catching lever 95, showing catch 96and projection 124 on which is seated the other end of spring 120. Alsoseen is one of a pair of pin-like cam followers 136 which, in theassembled, i.e., nested, twin-lever system, ride on the inclinedsurfaces 130 of camming lever 90, thereby being withdrawn into housing78 against the resilient force of spring 120.

FIG. 17 shows catch lever 95 as seen in the direction of arrow A in FIG.16. Seen is the pair of cam followers 136, advantageously extruded fromthe material of the blank prior to its being folded to produce theU-shaped profile, and the tongue-like projection 124 serving as a seatfor compression spring 120.

The following is a brief description of the different operational stagesof this embodiment. FIG. 18 represents the non-loaded device. As noweight is acting on wheel retainer 89 and, consequently, no force isacting on housing 78, heel 132, which controls the position of camminglever 90 relative to housing 78, is not acted upon by head 83 of cableferrule 82, thus permitting compression spring 120 to tilt catchinglever 95 in the clockwise sense, so that catch 96 will project fromhousing 78, while camming surface 92 is now largely inside housing 78.This is one of the limit positions of the lever system. It will beappreciated that this arrangement also precludes the possibility of thenon-loaded device being accidentally hoisted up into bracket 70, as theprojecting catch 96 will prevent the device from entering opening 72.

The first stage of hoisting up a spare tire is illustrated in FIG. 9.When the tire is mounted on wheel disk WD and the hoist lifts the tireoff the ground, the fill weight of the tire acts on housing 78,producing a reactive force exerted by head 83 of cable ferrule 82 onheel 132. This in turn produces a moment about pivot 94 of camming lever90, causing the latter to tilt in the counter-clockwise sense, therebydragging cam follower 136 down the camming surface 130 and thusretracting catch 96. At this stage, hoisting can proceed, as catch 96,having been retracted, is no longer intercepted by opening 72.

In FIG. 19, the upper end of the device has entered bracket 70, wih theretracted catch already beyond rim 74. At this instant, camming surface92 hits the edge of opening 72 and, with hoisting continuing, is pushedto the right, with the result that catch 96 returns to its projectinglimit position.

In FIG. 20, hoisting has been completed, camming surface 92 is insidehousing 78 and catch 96 fully projects. In case of cable failure asrepresented in FIG. 21, the loaded device drops for a short length untilcatch 96 is intercepted by rim 74, which of course breaks the fall.

A third embodiment of the device according to the invention is describedin FIGS. 22-26. There is seen in FIG. 22 a bracket 138, shown to bettereffect in FIG. 23, having a top member 140, a rear wall 142 and twolateral walls 144. Bracket 138, advantageously press-formed from asingle blank of sheet steel, is fixedly attached to a member of thevehicle's chassis. As can be seen in FIG. 23, each of the wing-likelateral walls 144 is provided with bearing means 146 for journals 148,seen in FIG. 24. In the cross-sectional view of FIG. 22, only the axes150 of journals 148 are marked. Journals 148 are advantageously integralparts of an injection-molded plastic lever 152 (see also FIG. 24), inthe upper part of which is provided a groove 154 for cable 156 to runalong. The lower part of lever 152 is in the form of two arms 158,provided at their ends with gripping projections 160. Further seen inFIG. 22 is a plunger 162 having an olive-shaped head 164, a relativelyslender stem 166 and a relatively broad shoulder 168 with asubstantially spherical surface on which a wheel-disk retainer 170 isfreely seated, the freedom of movement of which is limited by a collar172. Cable 156 passes plunger 162 via a bore 173.

The end of cable 156 is fixedly connected to a ferrule 174, with ahelical compression spring 176 serving as shock absorber and forcompensation for possible changes in tire width. Further shown is acable guide tube 178 and a flat spring 180 which exerts a clockwisemoment on lever 152.

In the operational stage shown, i.e., upon the spare tire being raised,tension in cable 156 exerts a counter-clockwise moment on lever 152,overcoming the clockwise moment produced by spring 180 and tilting lever152 into a first limit position, shown in FIG. 22, with the tilt beingstopped by the end 182 of rear wall 142 of bracket 138. In this positionof lever 152, head 164 of plunger 162 can enter the space defined bylever 152 and rear wall 142 from behind, gripping projections 160. Indoing so (FIG. 25), plunger head 164 forces lever 152 to tilt in aclockwise direction towards a second limit position in which the sparetire is fully raised and abuts against the aforementioned structuralcomponents of the vehicle chassis.

A situation of cable failure or break is illustrated in FIG. 26. Cable156 having broken, cable tension has dropped to zero and thecounter-clockwise moment produced by this tension has been eliminated,permitting spring 180 to tilt lever 152 fully into the second limitposition, in which gripping projections 160 are substantially verticallybelow plunger head 164. Head 164, having lost its support, drops and isintercepted and retained by gripping projections 160.

Although springs 26 and 176 are configured as helical compressionsprings, an appropriate modification of the harnessing of these springscould also permit the use of tension springs.

While the present invention was exemplified by means of its applicationto spare tires, it should be clear that the mechanical and structuralconcepts involved can also be applied to other types of liftable andlowerable loads.

It will be evident to those skilled in the art that the invention is notlimited to the details of the foregoing illustrated embodiments and thatthe present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed is:
 1. A device for securing the upper terminal positionof a liftable and lowerable object, comprising: cable means having ahoist-side end and an object-side end; a stationary bracket having arear wall and two lateral walls and provided with bearing means; levermeans located between the two lateral walls of said bracket and providedin its upper portion with journals whereby said lever means is pivotablymounted in the bearing means of said bracket and can assume first andsecond limit positions of tilt, said lever means being provided withgripper means at its lower end; plunger means carrying said object andkinematically connected to said cable means, said plunger means having acentral bore through which said cable means passes, and first springmeans attached to said stationary bracket and biasing said lever meanstowards the second limit position; wherein, in the first limit positionof said lever means, tension in the cable means causes the lever meansto tilt towards the bracket rear wall thereby permitting said plungermeans to enter a space defined by said lever means and said rear wall,thus forcing said lever means into the second limit position with thegripper means of the lever being located substantially vertically belowthe head of said plunger means, whereby, in case of cable failure, saidfirst spring means forces the lever means into the second limit positionand the plunger head is intercepted and retained by said gripper means.2. The device as claimed in claim 1, further comprising second springmeans for kinematically connecting said object-side end of said cablemeans to said plunger means.